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Subject: Re: [BUG] false positive in bt_index_check in case of short 4B
 varlena datum
From: Andrey Borodin <x4mmm@yandex-team.ru>
In-Reply-To: <af5smncUA1MzXNxa@paquier.xyz>
Date: Tue, 12 May 2026 14:17:27 +0500
Cc: Alexander Korotkov <aekorotkov@gmail.com>,
 Andres Freund <andres@anarazel.de>,
 Alexander Lakhin <exclusion@gmail.com>,
 Michael Zhilin <m.zhilin@postgrespro.ru>,
 pgsql-bugs@postgresql.org,
 Yura Sokolov <y.sokolov@postgrespro.ru>
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> On 9 May 2026, at 04:07, Michael Paquier <michael@paquier.xyz> wrote:
> 
> On Mon, May 04, 2026 at 10:20:04AM +0500, Andrey Borodin wrote:
>> However, I'd like to note that (VARSIZE_1B() < TOAST_INDEX_TARGET) is
>> constantly true for 8Kb+ pages.
> 
> How much slower?  I cannot imagine that it matters much in this code
> path, but you are getting me worried.


I think there will be no performance difference.

Change proposed by Alexander only prevents use of VARSIZE() against datum
that is VARSIZE_1B. AFAICS no actual behavior would change.

On some occasions we would have to normilize less tuples.


Best regards, Andrey Borodin.